(1) Field of the Invention
This invention is related to the means of attachment between the spoke and the rim of a vehicle wheel and between the spoke and hub of a vehicle wheel. This invention is particularly related to the connection of a spoke with a rim structure having a “double-wall” construction.
(2) Description of the Related Art
Bicycle wheel rims have historically been constructed to accept pneumatic tires that are designed to work in conjunction with an inner tube. This is the standard of the industry and is the arrangement that we are all familiar with. In this prior art configuration, the rim's tire bed includes a through-hole that is drilled through for passage of the spoke nipple. In a rim of “single-wall” construction, the spoke nipple bears directly against the rim's tire bed. In a rim of “double-wall” rim construction, the rim has two lateral walls, a tire bed and a spoke bed, with a cavity in between. The rim is drilled through both walls, piercing both the tire bed and the spoke bed, with the spoke bed recessed below the tire bed to accept the spoke nipples. Generally, the spoke is presented through the spoke bed from the inside diameter of the rim and the spoke nipple is presented for attachment to the spoke through the tire bed and from the outside diameter of the rim. With single-wall or double-wall rim constructions, a rim strip is utilized to protect the inner tube from the sharp edges associated with the holes and/or the spoke nipples. With rims of double-wall construction, the rim strip also serves to prevent the inner tube from extruding through the openings in the tire bed.
With the advent of tubeless tire technology, where the conventional inner tube is eliminated and the tires beads are sealed directly against the rim, it is desirable that the tire well be sealed and airtight to prevent air leakage from the tire cavity. This typically involves a rim of double-wall construction where the tire bed is sealed while the spoke bed is then adapted to accept the spokes. One method for sealing the tire bed is to eliminate the spoke holes in the tire bed. If the tire bed is not pierced for the spokes, then the only hole through the tire bed will be for the tire inflation valve, which may be constructed of rubber and is relatively easy to seal against the tire bed. An example of such a tubeless arrangement is outlined by Lacombe et al. in U.S. Pat. No. 6,443,533, where the tire bed remains unpierced and the spoke bed includes extruded spoke holes that are directly threaded with internal threads to accept special externally threaded spoke nipples.